Reactive plasma of a halogen, such as F or Cl, for etching or cleaning is used in a semiconductor manufacturing apparatus for use in a dry process or plasma coating in semiconductor manufacturing. Thus, members for use in such a semiconductor manufacturing apparatus require high corrosion resistance and generally include members composed of corrosion-resistant metals, such as Al subjected to alumite treatment and Hastelloy, and ceramics. In particular, electrostatic chuck members and heater members for supporting and fixing a Si wafer require high corrosion resistance and low dusting and are therefore made of corrosion-resistant ceramics, such as aluminum nitride, alumina, and sapphire. These materials are gradually corroded in long-term use and generate dust. Thus, there is a demand for higher corrosion-resistant materials. Mg compounds magnesium oxide and spinel are known to have higher corrosion resistance to halogen plasma than alumina. In particular, the corrosion resistance increases with the magnesium oxide content (for example, Patent Literature 1).
However, magnesium oxide reacts with water and carbon dioxide in the air and forms hydroxide and carbonate. Thus, the surface of magnesium oxide gradually deteriorates (a moisture resistance problem). When magnesium oxide is used in a member for a semiconductor manufacturing apparatus, therefore, semiconductor devices may be contaminated by decomposition gases of the hydroxide and carbonate or by magnesium oxide particles or dust formed by the decomposition of the hydroxide and carbonate. This retards the practical application of magnesium oxide. In order to improve the moisture resistance of magnesium oxide, a method utilizing solid solution of NiO or ZnO in magnesium oxide has been proposed (see, for example, Patent Literature 2).